Buick V6 - 3.8L 231 Oil Type?

Based on the intake casting number I was able to ascertain the motor I have in my FJ40 is a Buick V6 - 3.8L 231 (1976 I'm assuming). I've been able to nail down most of what I need for a tune up and oil change, but wanted some opinions from those in the know regarding what type of oil to use and am hoping someone knows how many quarts are required. I'm thinking of using Castrol Syntec 10W-30. Thoughts? Opinions?

anything of a reasonable grade will work just fine...5W30, 10W30, 10W40, 15W40.....all depends on how much you wanna spend. if spending more makes you feel better, go for it. Plenty of unwinable debates gone on over the years as to what is 'best'. Full synthetic caused my freshly rebuilt SBC to leak like a sieve. Add a Zinc/Phosphorus additive (cam break-in additive) if you are running a non-roller cam and you will be fine. Fill it to the full mark on the dipstick. That's how much it takes.

anything of a reasonable grade will work just fine...5W30, 10W30, 10W40, 15W40.....all depends on how much you wanna spend. if spending more makes you feel better, go for it. Plenty of unwinable debates gone on over the years as to what is 'best'. Full synthetic caused my freshly rebuilt SBC to leak like a sieve. Add a Zinc/Phosphorus additive (cam break-in additive) if you are running a non-roller cam and you will be fine. Fill it to the full mark on the dipstick. That's how much it takes.

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Thanks for the tips, especially the part about filling it to the full mark. Guess I'll go ahead and buy two five quart bottles. I don't think I'll go for the synthetic after reading what you typed. That would really suck re the leakage.

My family owned a couple vehicles with that motor back in the day. IIRC they liked a little heavier oil than 10w30. 10w40 is what we ran in them. Both vehicles lasted over 175K miles without a rebuild on the motors.

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